Open Source Mapping: GIS For The Rest Of Us.

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Data drives planning decisions, and those who have the data have the most power in making them. Unfortunately, it is usually governments and companies that have the data, and their decisions on planning and development impact our communities. The tools used to create and analyze data are expensive—for U.S. residents, a copy of ESRI’s ArcView GIS software is $1,500 for the most basic version. Most communities do not have the resources to purchase this type of software, nor do they have the ability to buy data collection tools such as a Trimble GeoExplorer. How can we involve communities in the creation and analysis of data so that they may help make and influence decisions about their neighborhoods?

Recent advances in technology, primarily the proliferation of GPS enabled cell phones, combined with increased interconnectivity via free WiFi, more people with home internet connections, lower costs of computers and the rise of open source software, is making it easier and cheaper for communities to become involved in planning decisions. A GPS enabled cell phone is a powerful tool for data creation. If you can take a photograph and find your location on Google Maps, you can then create a point map of referenced photographs. When you take a photograph with your phone, GPS data is embedded in the image. Uploading these images to Flickr, they can either automatically be placed on a map or you can point and click where they should go.

Flickr Showing Photographs Georeferenced. Source: Flickr.com

With a cell phone and a Flickr account, a community could create a map like the Burlington Pothole Map, showing the city where the streets are in need of repair.

A Map Showing Potholes In Burlington. Source: BurlingtonFreePress.com

If a community wanted to take it even further, a desktop GIS (geographic information system) application that is almost a complete replacement of ArcView can be had for free. Quantum GIS is an open source GIS application that runs on Windows and Macintosh – ArcView still only runs on Windows. With QGIS, users can

browse, edit and create a variety of vector and raster formats, including ESRI shapefiles, spatial data in PostgreSQL/PostGIS, GRASS vectors and rasters, or GeoTiff. You can create customised plugins and GIS enabled applications using Python or C++. Maps can be compiled for printing using the print composer1.

QGIS With Open Street Map Data. Source: qgis.org

Using a desktop GIS requires more knowledge than geo-referencing photographs, but if there is local knowledge, it gives a community almost the same tools as governments or large organizations. Using data to create a map in a desktop GIS is a big step forward for communities. But, the presentation of the map data is almost as important as the data itself. Well presented maps can speak volumes. One of the best tools for creating stunning maps is MapBox by TileMill. MapBox is free and open source. Originally running on Linux and Macintosh, a Windows version was recently released. MapBox allows you to import your data, and through their language Carto, a CSS like language, beautify your maps.

A MapBox Map: Ísland From Konstantin Käfer. Source: tiles.mapbox.com

There are also tools that will help a community create online maps. Leaflet.js is a very simple open source JavaScript mapping library. The library requires some programming knowledge, however, there are examples and plenty of documentation to help in learning to create a map. Because Leaflet.js is written in JavaScript the maps can be displayed on mobile phones and can use the geolocation features of new web browsers.

A Sample Leaflet.js Map with a Marker and a Popup. Source: leaflet.cloudmade.com

A Map of Open Street Map Data Displayed in Geoserver with OpenLayers. Source: geoserver.org

Finally, for those communities who want a complete GIS stack, they will need a server. GeoServer is a “Java-based software server that allows users to view and edit geospatial data.” With GeoServer, you can serve maps through Geo standards such as WMS. This allows anyone to connect to your server and display your data or add to it. Using Leaflet.js, communities can build websites on top of the server. Most importantly, with GeoServer, a community can build a full blown GIS application that allows the displaying, querying, editing and creation of data. Using a mobile phone, QGIS, TileMill, Leaflet.js, and GeoServer, a community can build their own full GIS stack that is almost equivalent to the commercial ESRI products. With these tools, a community can create and share data to affect change. These tools give the community a voice in planning decisions.